Sürdürülebilir Kalkınma Amaçları
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- MakaleAçık Erişim2022Investigation of gamma ray absorption levels of composites produced from copper mine tailings, fly ash, and brick dust
Külekçi, Gökhan
To date, heavyweight concretes have been produced from various heavy aggregates as radiation insulation materials, and their gamma ray absorption levels have been investigated. Many of the studies have used heavy aggregates instead of cement or coarse aggregates from composite material components. The present study prepared lightweight concretes using copper mine tailings, clay brick dust, and fly ash instead of fine aggregates. Some mechanical tests (density, compressive strength, and ultrasonic pulse velocity) were performed on composite blocks with dimensions of 5*5*5 cm, and radiation interaction parameters [linear absorption coefficient (cm−1), mass attenuation coefficient (cm2/gr), HVL (half-value layer) (cm), MFP (cm), and permeability (%)] were measured. Radiation interaction parameters were obtained using a HPGe gamma detector. Radiation measurements were performed at five different photon energies: 583 keV (133Ba), 609 keV (133Ba), 662 keV (137Cs), 911 keV (133Ba), 1173 keV (60Co), and 1332 keV (60Co). Additionally, the compressive strength and UPV values of composite materials were associated with their gamma ray permeability. Tests revealed that samples with the addition of copper mine tailings yielded the best energy absorption at all energy levels and that absorption decreased as the energy level increased. For example, with the increasing of the energy level, mass attenuation coefficients decreased. The highest mass attenuation coefficients were obtained as 0.128 cm2/g at an energy level of 583 keV in composites produced from copper mine tailings. On the other hand, it was measured at the same energy level as 0.069 cm2/g (a 46% decrease) in the composites produced with fly ash. In addition, it was observed that fly ash used as a fine aggregate did not have a significant effect on mass attenuation coefficient and could be used as a gamma shield if the material thickness was increased to an average of 14 cm. This study revealed that tailings materials could be used as radiation shields. This study also demonstrated that not using heavy aggregates and producing lightweight concrete in radiation shield production significantly reduced shield production cost.
- MakaleYalnız künye2021Investigation of fly ash added light concretes with respect to gamma radiation transmission properties of 133Ba and 137Cs
Külekçi, Gokhan
With the help of the developing concrete technology, light concrete and fly ash may be used in several concrete-related fields. To provide protection from radiation, which is one of the current problems of the world, several researchers have used fly ash, but very few researchers have worked on light concrete. To be protected from the effects of radiation, researchers have examined gamma radiation absorption properties by using heavy concrete and heavy aggregates. In this study, by using Class C fly ash at the doses of 30-50-100% instead of cement, three different light concretes were prepared. Density and compressive strength experiments were conducted on the composite blocks prepared with dimensions of 50*50*50 mm, and linear absorption coefficients (cm(-1)), mass attenuation coefficients (MAC) and Tenth value layer (TVL) radiation interaction parameters were measured. Radiation interaction parameters were obtained using an HP Ge gamma detector. For radiation measurements, four different photon energies as 583 keV (Ba-133), 609 keV (Ba-133), 661 keV (Cs-137) and 911 keV (Ba-133) were used. As a result of the analyses, it was determined that compressive strength decreased as the fly ash content increased, the lowest compressive strength values were obtained in the samples containing 100% fly ash among the prepared composites, and density increased as the fly ash content decreased. It was observed that, in the prepared composites, as the energy levels increased, the linear absorption coefficients also increased, and the samples containing 30% fly ash provided the best TVL value on the energy level of 911 keV. With this study, it was revealed that fly ashes that are used in many fields could be used as a radiation shield. Additionally, with this study, due to not using heavy aggregates and due to the production of light concrete in the production of radiation shields, the cost of shield production will significantly decrease.